Immunologic aspects of osteoporosis.
Osteoporosis is a major cause of morbidity in older people. There are a large number of risk factors for the development of osteoporosis. However, these risk factors eventually must mediate their effects through modulation of bone remodeling. A variety of compounds including hormones and nutrients modulate bone remodeling. In addition to these well-characterized substances, the immune system plays a role in bone remodeling through pro-inflammatory cytokines. Specifically, interleukin-1 (IL-1), IL-11, interferon-g are known to influence osteoclasts and osteoblasts. Recently, the cytokine IL-6 has joined ranks with these cytokines as a bone reactive agent. IL-6 has been shown to increase with age and menopause. Additionally, murine models suggest that IL-6 plays a central role in bone resorption. Finally, in vitro studies demonstrate that IL-6 induces osteoclast activity. In this review, we will discuss the pathogenesis of osteoporosis in the context of aging and IL-6.
Ershler
W B
WB
Gerontologic Research Center, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
Harman
S M
SM
Keller
E T
ET
D000368:Aged; D000728:Androgens / Q000378:metabolism; D000818:Animals; D016723:Bone Remodeling; D002452:Cell Count; D016207:Cytokines / Q000276:immunology; D004967:Estrogens / Q000378:metabolism; D050723:Fractures, Bone; D015577:Geriatric Assessment; D006728:Hormones / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000276:immunology*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010024:Osteoporosis / Q000209:etiology / Q000276:immunology*; D019947:Receptors, Interleukin-6 / Q000276:immunology*; D012307:Risk Factors
D000728:Androgens; D016207:Cytokines; D004967:Estrogens; D006728:Hormones; D015850:Interleukin-6; D019947:Receptors, Interleukin-6